1. Field of the Invention
The present invention relates to an ink jet recording ink (hereinafter abbreviated as an “ink”) which is suitable for an ink jet recording method, and to a recording method and recording apparatus which use this ink. The present invention particularly relates to an ink which is free from a problem concerning curling of a recording medium containing cellulose even when the ink as an aqueous ink is applied in a large amount onto the recording medium, and an ink jet recording method and an ink jet recording apparatus which have good response during ejection at a high drive frequency and good startup properties.
2. Description of the Related Art
In ink jet recording methods, recording is made by spouting minute ink droplets and adhering them to a recording medium such as paper. In such methods, there is a thermal system in which an electrothermal energy converter is used as an ejection-energy supply unit to apply thermal energy to an ink to generate bubbles to eject ink droplets. With such a system, high-density multi-nozzles in an ink jet recording head can be easily realized, and it has been reported that high-resolution and high-quality images can be recorded at high speed (see, for example, Japanese Patent Publication Nos. S61-059911, S61-059912 and S61-059914).
Recently, the size of ink droplets ejected from a single nozzle has come to be made smaller for the purpose of providing very high-quality ink jet recorded images on a level with silver halide photographs. Currently, ink jet printers are commercially available in which an ink droplet amount is about 5 pL (pico-liter(s)) or smaller. There is also a need for recording speed to be greatly increased. In view of the need for higher speed, the handling of higher drive frequencies and the improvement of startup properties are urgent tasks.
Further, inks used in ink jet recording generally include water as a principal component and additionally a water-soluble high-boiling solvent such as glycol for the purpose of, for example, preventing drying and improving resistance to sticking on the ink jet recording head. When such inks are used to conduct recording on a recording medium containing cellulose as typified by plain paper or trace quantity coated paper, a problem is raised in that the recording medium warps, or in other words “curls”, if they are applied in a large amount to a region not smaller than a certain area in a short period of time. The occurrence of the curling phenomenon has not been a major problem in conventional recording in which characters are primarily recorded, which has been prevalent in recording, because the applied amount of ink is relatively small. However, the curling has become an important problem to be solved because of the need to apply a large amount of ink onto plain paper or the like when recording Internet homepages or photographic images, as widely carried out in recent years.
In order to solve the problem, aqueous ink compositions containing various anti-curling solvents have been proposed (see, for example, Japanese Patent Application Laid-Open Nos. H06-157955 and H11-012520) Although a certain effect on curling resistance (which means that the effect of suppressing the occurrence of curling is exhibited) is achieved by using these substances, further improvements are sought in respect of the compatibility of responsiveness upon ejection at high drive frequencies and startup properties with curling resistance.